Ten years after waging a bloody campaign to gain control over his own province, powerful samurai warlord Oda Nobunaga has seized much of Central Japan, including the nation’s capital, Kyoto. Now, driven by a towering ambition, he dreams of crushing the powerful clans who still oppose his rule. And for the first time in over a century, uniting all of Japan under one banner. But Nobunaga’s legendary brutality has caused widespread anger. Across the nation, powerful enemies now plot his demise.

This brilliant docuseries is an exploration of the feudal Japan from 1551 to 1616 , during the final phase of the Sengoku period (The Age of Warring States), when several powerful daimyo (warlords) fought to become absolute ruler. It features reenactments of historical events and commentary by voice-over artist Hiro Kanagawa and outstanding historians.
In the first episode, Oda Nobunaga becomes head of the Oda clan upon the death of his father, but this causes problems with family members who compete for control.

The film is the inside track on the World's most influential weapon. For over a thousand years this weapon dominated the battlefields of Japan, instilled fear and terror into every enemy it faced, and created a new spiritual way of life that lasts through to the present day. The Samurai sword – a weapon so technologically perfect in structure, so formidable in strength and so beautiful in creation. For the first time unique access has been granted and we travel into the core of the ancient foundries, sword-smiths and fighting schools to reveal what makes the so-called perfect sword. This is a no holds barred look at one of the most iconic man-made objects ever forged.

Sagan discusses the story of the Heike crab and artificial selection of crabs resembling samurai warriors, as an opening into a larger discussion of evolution through natural selection (and the pitfalls of intelligent design). Among the topics are the development of life on the Cosmic Calendar and the Cambrian explosion; the function of DNA in growth; genetic replication, repairs, and mutation; the common biochemistry of terrestrial organisms; the creation of the molecules of life in the Miller-Urey experiment; and speculation on alien life (such as life in Jupiter's clouds). In the Cosmos Update ten years later, Sagan remarks on RNA also controlling chemical reactions and reproducing itself and the different roles of comets (potentially carrying organic molecules or causing the Cretaceous–Paleogene extinction event).